The present invention relates to a liquid chromatograph. More particularly, it concerns a liquid chromatograph that makes it possible to know of accurate volume of sample added to a column.
For the prior liquid chromatograph, volume of sample injected to the column is an important parameter for investigating and analyzing the chromatogram data obtained. If the chromatogram data are preserved, it is desirable to also store the volume of the sample injected to the sample separating column. So, it is usual to preserve the volume of the sample added to the sample retainer frequently called the sample loop as the volume of the sample injected to the sample separating column together with the obtained chromatogram data if there is an automatic sample injecting device for measuring the volume of the sample injected to the sample separating column with use of a syringe and the like. Or, the sample retainer capacity should be preserved as the volume of the sample injected to the sample separating column together with the obtained chromatogram data if there is an automatic sample injecting device for measuring the volume of the sample injected to the sample separating column with use of the sample retainer.
However, the use of the sample retainer described above has the disadvantage that if the volume of the sample added to the sample retainer exceeds over the capacity of the sample retainer, the volume of the sample added to the sample retainer is stored as the volume of the sample injected to the sample separating column in spite of the same volume of the sample injected to the sample separating column as the capacity of the sample retainer. This is due to no account of the fact that the volume of the sample injected to the sample separating column is determined in terms of both the volume of the sample added to the sample retainer and the capacity of the capacity of the sample retainer. Also, the sample retainer has the disadvantage that even if the volume of the sample added to the sample retainer is less than the capacity of the sample retainer, the volume of the sample added to the sample retainer may not be equal to the volume of the sample added from the sample retainer to the sample separating column. This is due to the fact that as the sample is diffused with the eluate in the piping connected with the sample retainer or in the sample retainer, all the added sample cannot be always remained in the sample retainer.